1. Field of the Invention
The present invention relates to a safety system for connecting a pressure medium source, a user of the pressure of the pressure source, and a pressure reservoir.
2. Description of the Prior Art
With a known safety device for connecting a pressure source, user and pressure reservoir, the three-way valve has a negative overlap. Such valve, especially a ball cock assembly, is not tight due to imprecise connections and/or insufficiently precise finishing, permitting pressure medium to penetrate through this valve, even when the valve is closed. If the reservoir line is of lower resistance than the line to the supply container, and the leakage penetrates from the closed three-way valve to the empty reservoir. This is a particular disadvantage when the pressure reservoir is removed. Such system is disclosed in DE-PS No. 32 27 776.
One known valve device is configured as four-part valve with three user connections, which should be fed pressure medium in a special way from a pressure medium source. With the known valve device, an arrester valve closing in the direction of the reservoir port is connected to a passage connecting the pressure port and the reservoir port. One of the users is attached in the passage connecting the pressure port with the arrester valve. An additional arrester valve, opening in the direction of the user, is arranged in this passage before this user. Such system is disclosed in DE-OS No. 29 35 949.